Review Questions for Third Exam
Chapter 36 and 38
: proton pump, co-transport, turgor pressure, water potential, back pressure,
solute pressure, mycorrhizae, endodermis, root pressure, transpirational pull, bisexual
vs. unisexual flowers, incomplete flowers, pericarp, transgenic plants.
Understand how proton pumps and co-transport are important for movement of
molecules and ions across plant cell membranes.
Proton pumps actively transport H
out, anions and solutes in.
2. Understand what water potential and turgor pressure mean.
Why do water molecules
flow to more negative water potentials? How is back pressure and solute pressure
involved? Be able to predict water flow based on Wp and Ws.
Because evaporation at
leaves creates transpirational pull which draws water up. Be able to use the
equation given in class in an example.
3.What is guttation? Explain how water potential difference drives water flow from roots,
up the trunk, and into and out of leaves. Be familiar with the general values of water
Guttation is dew when increased root solute concentration at
night draws in so much water that it forms drops on the leaves. Water potential
becomes more negative as you move up the trunk, resulting in water flowing from
roots to the trunk and leaves.
4.How are guard cells and stomata involved in regulating the movement of gases and
water in and out of leaves?
What molecular mechanism causes stomata to open or
Know guard cells open when turgid (due to inflow of K
which draws water
in and makes cells turgid).
This allows carbon dioxide in and oxygen out.
cells also open when carbon dioxide level gets to low within leaves.
5. What two mechanisms are involved in transport of sugars from leaves to roots?
Hydrostatic flow down sieve tube elements and solute co-transport across
phloem cell membranes (review figure in book)
6.Describe the series of steps that occur as sperm fertilize the ovule in the plant ovary.
What is the endosperm and why is it important? What develops into the seed?
Male gametogenesis (formation of pollen), growth of pollen tube,
fertilization, formation of fruit, seed dispersal.
7. Give an example of a plant variety produced by crossing, artificial selection and
What are the pluses and minuses of genetically engineered
Corn and wheat are the result of crosses of natural plants and
artificial selection over thousands of years.
Now we can rapidly genetically
engineer plants to give them disease or pest resistance.
But what happens if
genes spread to closely related weeds, or if beneficial insects are affected?
Chapters 33 and 34
: radial vs. bilateral symmetry, acoelomate vs. pseudocoelomate vs.
coelomate, protostome vs. deuterostome, enterocoelous vs. schizocoelous, lophophore,